1. Field of the Invention
The present invention relates to a flash fusing apparatus and more particularly to a flash fusing apparatus wherein the toner is heated and fused on the recording paper by means of the flash of light. The flash fusing apparatus of the present invention is applied for use in the laser beam printers and the facsimile equipments etc. wherein the image is recorded on the recording paper by the toner.
2. Description of the Prior Art
A conventional flash fusing apparatus is disclosed in, for example Japanese Utility Model No. 3562/1986, and applied for use in the laser beam printers and the facsimile equipment etc.. In such a flash fusing apparatus, the toner is attached on the recording paper by the electrostatic energy for development process, and in a fusing process the toner is heated and fused on the recording paper by flash of the xenon flash lamp etc. so as to form the image on the recording paper by the toner.
In this flash fusing apparatus, it is desirable to obtain the sharp image on the recording paper without dirty marks or spots appearing on the paper. The spots or smudges occur on the recording paper through the gas generated from the toner when the toner is heated under high temperature condition for the fusing process.
The conventional flash fusing apparatus having a gas suction mechanism is shown in FIG. 12. Toners 84 are arranged on the upper surface of a recording paper 82. The toners 84 are heated and melted with flash of by a xenon flash lamp 81 and thus fused on the recording paper 82. The xenon flash lamp 81 is disposed in a lamp housing 86. The lamp housing 86 has a glass plate member 85 at the bottom portion thereof. The glass plate member 85 is positioned oppositely to the upper surface of the recording paper 82.
Epoxy based toner or polystyrene base toner 84 is used commonly as the toner 84 for the flash fusing apparatus. When the fusing process is carried out, gas generates from the toner 84 according to the abrupt temperature rise of the toner 84 by heating. The generated gas attaches on the upper surface of the recording paper 82 and spots appear also on the upper surface of the recording paper 82. Further, the generated gas attaches also to the surrounding members of the lamp housing 86 such as the glass plate member 85, so that the quantity of light flash of the xenon flash lamp 81 is reduced.
As one of the spots countermeasures in the conventional flash fusing apparatus, a suction hole member 83 as the suction mechanism is provided at the lower portion of one end of the glass plate member 85 as shown in FIG. 12. The generated gas from the toner 84 is suctioned and removed by the suction hole member 83.
However, even when the above mentioned spot countermeasures for the flash fusing apparatus having gas suction mechanism is carried out, it is impossible to get rid of the defects caused by gas generation phenomenon. The spots on the recording paper 82 remain unchanged. Moreover, it is necessary to practise at periodic intervals the cleaning of the glass plate member 85 of the xenon flash lamp 81.
In order to prevent the generation of gas from the toner during the fusing process, flash intensity or the fusing energy. According to the adoption for lowering of the flash intensity, the occurrence of spots may be reduced, however, the adhesion force of the toner with the recording paper is weakened, namely the toner is detached easily from the recording paper.